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package org.glassfish.grizzly.asyncqueue;

import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.Context;
import org.glassfish.grizzly.ProcessorResult;

/**
 * Common interface for {@link AsyncQueue} processors.
 * 
 * @author Alexey Stashok
 */
public interface AsyncQueue {
    String EXPECTING_MORE_OPTION =
            AsyncQueue.class.getName() + ".expectingMore";
    
    enum AsyncResult {
        COMPLETE(ProcessorResult.createLeave()),
        INCOMPLETE(ProcessorResult.createComplete()),
        EXPECTING_MORE(ProcessorResult.createComplete(EXPECTING_MORE_OPTION)),
        TERMINATE(ProcessorResult.createTerminate());

        private final ProcessorResult result;
        
        AsyncResult(final ProcessorResult result) {
            this.result = result;
        }

        public ProcessorResult toProcessorResult() {
            return result;
        }
        
    }
    
    /**
     * Checks whether there is ready data in {@link AsyncQueue},
     * associated with the {@link Connection}.
     * 
     * @param connection {@link Connection}
     * @return <tt>true</tt>, if there is ready data,
     *         or <tt>false</tt> otherwise.
     */
    boolean isReady(Connection connection);
    
    /**
     * Callback method, which is called async. to process ready
     * {@link AsyncQueue}, which are associated with the given
     * {@link Connection}
     * 
     * @param context {@link Context}
     * @return {@link AsyncResult}, depending on async queue status.
     */
    AsyncResult processAsync(Context context);
    
    /**
     * Callback method, which is called, when {@link Connection} has been closed,
     * to let processor release a connection associated resources.
     * 
     * @param connection {@link Connection}
     */
    void onClose(Connection connection);
    
    /**
     * Close <tt>AsyncQueueProcessor</tt> and release associated resources
     */
    void close();
}
